SFI SYSTEM, Diagnostic DTC:P2120, P2122, P2123, P2125, P2127, P2128, P2138

DTC Code DTC Name
P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit
P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

DESCRIPTION

Tech Tips


  • This Electronic Throttle Control System (ETCS) does not use a throttle cable.

  • These DTCs relate to the accelerator pedal position sensor.

The accelerator pedal position sensor is built into the accelerator pedal sensor assembly and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type sensor and uses Hall-effect elements in order to yield accurate signals even in extreme driving conditions, such as at high speeds as well as very low speeds. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0.5 V and 4.75 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the accelerator pedal position sensor itself.

The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

B003VA6E08
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • ECM

 Comes on DTC stored
P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • Open in VCPA circuit

  • Open or ground short in VPA circuit

  • ECM

 Comes on DTC stored
P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input VPA is 4.8 V or higher for 2.0 seconds or more (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • Open in EPA circuit

  • ECM

 Comes on DTC stored
P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • ECM

 Comes on DTC stored
P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic).

  • Accelerator pedal sensor assembly

  • Open in VCP2 circuit

  • Open or ground short in VPA2 circuit

  • ECM

 Comes on DTC stored
P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input

Both of the following conditions continue for 2.0 seconds or more (1 trip detection logic):

(a) VPA2 is 4.8 V or higher.

(b) VPA is between 0.4 V and 3.45 V.

  • Accelerator pedal sensor assembly

  • Open in EPA2 circuit

  • ECM

 Comes on DTC stored
P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

Either of the following conditions continues for 2.0 seconds or more (1 trip detection logic):

(a) The difference between VPA and VPA2 is 0.02 V or less.

(b) VPA is 0.4 V or less, and VPA2 is 1.2 V or less.

  • Short between VPA and VPA2 circuits

  • Accelerator pedal sensor assembly

  • ECM

 Comes on DTC stored

Tech Tips

When any of these DTCs are output, check the accelerator pedal position sensor voltage using the GTS. Enter the following menus: Powertrain / Engine / Data List / All Data / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

Trouble Area Accelerator Pedal Fully Released Accelerator Pedal Fully Depressed
Accel Sensor Out No. 1 Accel Sensor Out No. 2 Accel Sensor Out No. 1 Accel Sensor Out No. 2
Open in VCP circuit 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V
Open or ground short in VPA circuit 0 to 0.2 V 1.2 to 2.0 V 0 to 0.2 V 3.4 to 4.75 V
Open or ground short in VPA2 circuit 0.5 to 1.1 V 0 to 0.2 V 2.6 to 4.5 V 0 to 0.2 V
Open in EPA circuit 4.5 to 4.98 V 4.5 to 4.98 V 4.5 to 4.98 V 4.5 to 4.98 V
Normal condition 0.5 to 1.1 V 1.2 to 2.0 V 2.6 to 4.5 V 3.4 to 4.75 V

Tech Tips

Accelerator pedal positions are expressed as voltages.

MONITOR DESCRIPTION

When either output voltage of VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is more than the threshold, the ECM determines that there is a malfunction in the accelerator pedal position sensor. The ECM then illuminates the MIL and stores a DTC.

Example:

When the output voltage of VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully depressed, DTC P2122 is stored.

MONITOR STRATEGY

Required Sensors/Components Accelerator pedal sensor assembly
Frequency of Operation Continuous

COMPONENT OPERATING RANGE

All of the following conditions are met -
VPA voltage Higher than 0.4 V, and less than 4.8 V
VPA2 voltage Higher than 1.2 V, and less than 4.8 V
Difference between VPA and VPA2 voltages Higher than 0.02 V

CONFIRMATION DRIVING PATTERN

B003TUKE36

  1. Connect the GTS to the DLC3.

  2. Turn the engine switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the GTS on [A].

  6. Fully depress and release the accelerator pedal [B].

  7. Check that 5 seconds or more have elapsed since the engine switch is turned on (IG).

  8. Enter the following menus: Powertrain / Engine / Trouble Codes [C].

  9. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  10. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

  11. Input the DTC: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.

  12. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] and [C] again.

FAIL-SAFE

When DTC P2120, P2121, P2122, P2123, P2125, P2127, P2128 or P2138 is stored, the ECM enters fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM limits the engine output. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles.

Fail-safe mode continues until a pass condition is detected, and the engine switch is turned off.

WIRING DIAGRAM

B003XAOE30
*a Accelerator Pedal Position Sensor (Accelerator Pedal Sensor Assembly)

CAUTION / NOTICE / HINT

Tech Tips

Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. READ VALUE USING GTS (ACCEL SENSOR OUT)


    1. B003V89C05
      *a Fully Depressed
      *b Fully Released

      Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / All Data / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.


      Powertrain > Engine > Data List
      Tester Display
      Accel Sensor Out No.1
      Accel Sensor Out No.2

    5. Read the value displayed on the GTS.

      Standard Voltage
      Accelerator Pedal Operation Accel Sensor Out No. 1 Accel Sensor Out No. 2 Difference between Accel Sensor Out No. 1 and Accel Sensor Out No. 2
      Fully Released 0.5 to 1.1 V 1.2 to 2.0 V More than 0.02 V
      Fully Depressed 2.6 to 4.5 V 3.4 to 4.75 V
      Result
      Proceed to
      OK
      NG

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

  2. CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL SENSOR ASSEMBLY - ECM)


    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A52-6 (VPA) - A76-29 (VPA) Always Below 1 Ω
      A52-5 (EPA) - A76-20 (EPA) Always Below 1 Ω
      A52-4 (VCPA) - A76-23 (VCPA) Always Below 1 Ω
      A52-3 (VPA2) - A76-28 (VPA2) Always Below 1 Ω
      A52-2 (EPA2) - A76-21 (EPA2) Always Below 1 Ω
      A52-1 (VCP2) - A76-22 (VCP2) Always Below 1 Ω
      A52-6 (VPA) or A76-29 (VPA) - Body ground Always 10 kΩ or higher
      A52-4 (VCPA) or A76-23 (VCPA) - Body ground Always 10 kΩ or higher
      A52-3 (VPA2) or A76-28 (VPA2) - Body ground Always 10 kΩ or higher
      A52-1 (VCP2) or A76-22 (VCP2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ACCELERATOR PEDAL SENSOR ASSEMBLY)


    1. B003W0NC14
      *a

      Front view of wire harness connector

      (to Accelerator Pedal Sensor Assembly)

      Disconnect the accelerator pedal sensor assembly connector.

    2. Turn the engine switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A52-4 (VCPA) - A52-5 (EPA) Engine switch on (IG) 4.5 to 5.5 V
      A52-1 (VCP2) - A52-2 (EPA2) Engine switch on (IG) 4.5 to 5.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ECM Click here

    OK

  4. REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY


    1. Replace the accelerator pedal sensor assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL SENSOR DTCS)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Clear the DTCs.


      Powertrain > Engine > Clear DTCs

    5. Turn the engine switch off and wait for at least 30 seconds.

    6. Turn the engine switch on (IG) and turn the GTS on.

    7. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    8. Enter the following menus: Powertrain / Engine / Trouble Codes.

    9. Read the DTCs.


      Powertrain > Engine > Trouble Codes
      Result
      Result Proceed to
      DTC P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 are output A
      DTC is not output B

    A

    REPLACE ECM Click here

    B

    END